1. Field of the Invention
This invention relates to an internal bone buttress plate and, more particularly, to a bone buttress plate for fixating a fractured hindfoot and a method of using the same.
2. Description of the Related Art
Displaced intra-particular fractures of the calcaneus, or calcaneum, are one of the most disabling of fractures. A crushed calcaneum often divides into a number of fragments with one or more fragments displacing from their original positions. The fragmented and disorganized calcaneum loses its height and begins to bulge. As the calcaneus bulges, the heel broadens. The longitudinal arch in the foot is lost and the Achilles tendon lengthens. A longer Achilles tendon causes excessive upward flexion in the foot. The initial pain and swelling rarely diminish after the fracture has healed, and later problems develop due to scarring of the nerves, tendons, and muscles. If the calcaneum is permitted to heal in this deformed condition, the function of the foot is rendered nearly useless.
Orthopedic surgeons have begun using open reduction and internal plate fixation to restore a displaced and fragmented calcaneus. Leung et al. discuss buttressing the lateral wall of the calcaneum with plates designed for cervical applications [Operative Treatment of Displaced Intra-Articular Fractures of the Calcaneum, 75-B The Journal of Bone and Joint Surgery, 196 (March 1993)]. Eastwood et al. use a common 3.5 mm "Y" shaped reconstruction plate to stabilize a three-fragment calcaneus [Intra-Articular Fractures of the Calcaneum, 75-B The Journal of Bone and Joint Surgery, 189, 192 (March 1993)]. O'Farrell et al. show a common strip plate contoured to the shape of the calcaneus lateral wall to stabilize lateral wall fragments [Fractures of the os calis. improved results with internal fixation, 24 Injury 263 (1993)]. Crosby et al. use a common "H" plate to restore a two-fragment intra-articular calcaneus fracture [Open Reduction and Internal Fixation of Type II Intra-Articular Calcaneus Fractures, 17 Foot & Ankle International 253, 254 (May 1996)]. Though the above plates may have functioned satisfactorily in two- and three-fragment fractures, the procedures often required the use of additional pins, screws, and K-wires, and surgeons have also had to add bone graft to support a central articular fragment. Since the calcaneus can fracture into four or more fragments, a fixation plate designed specifically for the possible fracture patterns of the calcaneum, without the need for bone graft or additional pins, screws, or wires, is required.
In another publication Kerr et al. discuss early operative results using a specialized AO calcaneal fracture plate [AO Calcaneal Fracture Plate, 27 Injury: International Journal of the Care of the Injured, 39 (1996)]. Though this plate was designed for calcaneal fractures, the plate itself is structurally weak and has been known to fracture when subjected to the plantarward forces of the foot while the patient is walking. Since the lateral cortex of the calcaneus is always severely comminuted, screw fixation of the central fragment is also complicated and the plate design causes the bone screws to anchor into mushy bone fragments. A further complication with this plate design is "blindly" anchoring bone screws into the sustentaculum from a lateral approach. This "blind" procedure places the adjacent neurovascular structures at risk.
There is, accordingly, a need in the art for a bone plate specifically designed for restoration of a severely displaced calcaneus, a plate design which could replace the need for bone grafting, a plate designed to provide a firm anchor for mechanical fasteners passing through the severely comminuted calcaneus lateral cortex, and a plate design which is structurally sound to withstand the plantarward forces imparted during walking.
It is, therefore, an object of the present invention to provide an internal bone buttress plate capable of withstanding the plantarward forces imparted on the plate while the patient is walking.
It is another object of the present invention to provide an internal bone buttress plate designed to minimize the need for additional pins, screws, or wires when restoring a severely displaced calcaneus.
It is another object of the present invention to provide an internal bone buttress plate designed to reduce the need for bone grafting.
It is another object of the present invention to provide an internal bone buttress plate designed to bridge a severely comminuted calcaneus lateral cortex and to provide a solid anchor for mechanical fasteners into the sustentacular region.
It is another object of the present invention to provide an internal bone buttress plate designed to secure mechanical fasteners into the sustentacular region without risking adjacent neurovascular structures.
It is another object of the present invention to provide an internal bone buttress plate designed to improve fixation to a large body fragment and to an anteromedial fragment.
Other objects and advantages of the present invention will be more fully apparent from the ensuing disclosure and appended claims.